Life Impact The University of Adelaide

Field failures are not always due to resistance. (verify with a test)

Getting the most out of DIM herbicides

• Spraying younger plants vs waiting to ‘get them all’

• By default, earlier spraying

• Younger weeds

• warmer conditions

• Less chance of frost

• Reduced control when ryegrass stressed

• Spray before frost vs after frost

Slide 1

Improved efficacy

Life Impact The University of Adelaide

Effect of cold period/ frost before and after clethodim treatment on ryegrass

1 100

20

40

60

80

100

S No FrostS Frost PreS Frost Post

Clethodim (g ha-1)

Dry

wei

gh

t (%

co

ntr

ol)

2012Frost or cold period before or after

spraying can reduce clethodim efficacy

• NF = no frost, • FBS= frost before spray• FAS= frost after spray

Life Impact The University of Adelaide

Managing clethodim resistant ryegrass in canola- IWM strategies.

• Reduce seedbank to take pressure of DIMs eg. knockdowns, pre-emergent & seed-set control

• Seed-set control- manage survivors/ late germinators.

• Target young weeds

• Warmer temp’s can increase DIM activity

• Frost after clethodim application reduces efficacy.

• Addition of low rate Factor (80g/ha) may improve clethodim activity

• Rotate- glyphosate, TT, CLR

• Alternative MOA herbicides